The invention relates to a transceiver and related switching method applied therein, and more particularly to a transceiver having an on-chip Balun and an on-chip TR (Transmit/Receive) switch, and a related method.
In a conventional transceiver, a TR (Transmit/Receive) switch is a device arranged to switch between a transmitter and a receiver of the transceiver. When the transceiver operates under a transmitting mode, the TR switch is arranged to couple the pre-transmitted signal outputted from the power amplifier to the antenna. When the transceiver operates under a receiving mode, the TR switch is arranged to couple the receiving signal of the antenna to the receiver. Two problems may arise from the conventional TR switch. The TR switch has intrinsic loss to the signal as it passes through because the TR switch may not be perfectly impedance matched with the transmitter and the receiver. The TR switch may also malfunction due to the large swing of the pre-transmitted signal when the transceiver operates under the transmitting mode.
For a differential communications system, an off-chip transformer balun (balanced/unbalanced) is further used to convert the signals between single ended and differential. An off-chip transformer balun will cause the overall cost higher because of the additional work of installing the off-chip transformer balun into the transceiver. Moreover, the off-chip transformer balun may occupy a large area of the PCB (Printed Circuit Board), which also increases the total cost.
Providing a low cost and low loss transceiver for the differential communications system is therefore a significant concern in this field.